Liquid-development type electrophotographic apparatus including paper drier means

ABSTRACT

A drier for drying copying paper in a liquid development type electrophotography apparatus includes a pair of squeegee rollers, and a pair of drier rollers provided next to the squeegee rollers. The peripheral surface of at least one of the drier rollers consists of a liquid-absorbing material. Air is evacuated from within a perforated endless belt to suck paper thereagainst for purposes of transportation. This air is moved past an exposure lamp where the air is heated and dried. The air is then blown against the liquid absorbing material and against copying paper passing therethrough.

United States Patent Su uk 1 Sept. 5, 1972 [54] LIQUID-DEVELOPMENT TYPE[56] References Cited ELECTROPHOTOGRAPHIC APPARATUS INCLUDING PAPERUNTTED STATES PATENTS DRIER MEANS 3,282,177 11/1966 Stanton ..355/l3,345,925 /1967 Ostensen ..355/ 10 [72] Inventor: Shigeru Suzuki,440-Marooka-cho, 3,345,926 10/ 1967 Tiger et al ..355/l0 X Kohoku-ku,Kanagaua-ken, 3,441,345 4/1969 Kolibas ..355/l0 Yokohama-shi, JapanPrimary Examiner-Samuel S. Matthews [22] Filed. July 1971 AssistantExaminer-Fred L. Braun 1 1 pp 167,745 Attorney-Erich H. Waters et a1.

Related US. Application Data [57] ABSTRACT [63] Continuation-impart ofSer. No. 783,550, Dec. A drier for drying copying Paper in a liquiFldevelop 13 1963, abandoned ment type electrophotography apparatusincludes a pair of squeegee rollers, and a pair of drier rollersprovided next to the squeegee rollers. The peripheral sur- [30] ForelgnApphcat'on Pnomy Data face of at least one of the drier rollers consistsof a Dec. 20, 1967 Japan ..42/81182 liquid-absorbing material Air isevacuated from within a perforated endless belt to suck paper [52] US.Cl. ..355/10, 34/70, 34/155, thereagainst for p p of transportation Thisair is /89 A moved past an exposure lamp where the air is heated [51]Int. Cl. ..G03g 15/10 and dried. The air is then blown against theliquid ab- [58] Field of Search ..355/3, 10; 95/89 R, 89 A; sorbingmaterial and against copying paper passing 34/70, 151, therethrough.

9 Claims, 4 Drawing Figures PATENTEDsEP 51972 SHEET 1 BF 4 FIG.

PATENTEDS-EP S1972 3.689.147

I sum 2 or 4 FIG; 2

PATENTEUSEP 5 m2 SHEU t [If 4 LIQUID-DEVELOPMENT TYPEELECTROPHOTOGRAPHIC APPARATUS INCLUDING PAPER DRIER MEANS OTHERAPPLICATIONS This is a continuation-impart of earlier application, Ser.No. 783,550, filed Dec. 13, 1968 and now abandoned.

FIELD OF INVENTION The present invention relates to copying paper drierdevices for electrophotographic apparatus of the type which employs aliquid development system.

BACKGROUND In electrophotographic devices of the type mentioned above,it is conventional to place a pair of squeegee rollers immediatelyfollowing a developer tank to receive copying paper which after passingthrough the squeegee rollers is dried by the flow of ambient or heatedair.

In an electrophotographic device of the type in connection with which aphotoconductive layer consisting of a zinc oxide composition constitutesa coating on the copying paper, the photosensitive surface of saidcopying paper is smooth and a film of developer solution will remain onthe smooth surface even after passage of the copying paper through thesqueegee rollers. This developer solution film cannot be eliminatedeasily in a subsequent drying process and, as a result, the copyingpaper comes out of the machine incompletely dried.

Drying devices are known for various purposes. Thus, for example theMinnis US. Pat. No. 1,982,116 relates to a fruit dryer wherein rollersare employed each of which is covered with a hygroscopic material suchas felt. Such patents however, do not generally relate to theimprovements of the invention.

The Jenkins US. Pat. No. 3,431,050 relates to an electrophotographiccopying machine which employs pressure rollers for positioning developedcopy paper at the exit of a developer liquid tank and a heater fordrying this copy paper. The technique employed for drying copy paper isnot very efficient nor effective and the apparatus disclosed by thispatent fails to employ improvements of the invention, such as a blotterroller as described in greater detail hereinafter.

SUMMARY OF INVENTION It is an object of the present invention to avoidthe defects mentioned above.

It is a further object of the present invention to provide an improvedcopying paper dryer device which effectively and efficiently driescopying paper upon the exit of the same from a developer tank.

Yet another object of the invention is to provide an improved dryerdevice which efficiently makes use of air available within the equipmentwhile efficiently utilizing an exposure lamp to heat and dry the airbefore the air is further employed for drying the blotter roller and forfurther drying the paper after it has passed through the blotter roller.

In achieving the above and other objects of the invention there isprovided a copy paper dryer for a liquid developing typeelectrophotographic reproduction apparatus which comprises a lightsource for the exposure of a photosensitive sheet and a developer tankcontaining a liquid developer. Furthermore, there is provided means forfeeding the exposed photosensitive sheet into and through the liquiddeveloper in the developer tank. This means includes a perforatedendless belt defining an internal chamber adapted to engage theaforesaid sheet.

A pair of squeegee rollers is provided at the exit of the tank toreceive the sheet therefrom. A pair of drier rollers is positionedadjacent the squeegee rollers and downstream of the same for receivingthe sheet therefrom. One of the drier rollers includes an outer coatingof a liquid absorbing material. The other of the drier rollersisconstituted of a hard material which presses the photosensitive sheetinto pressure contact with the first said roller.

In accordance with the invention there is provided means to evacuate airfrom the internal chamber of the belt and move the same past the lightsource to heat and dry the air and to discharge the thusly heated anddried air, first against the liquid absorbing material of said oneroller and then into contact with the photosensitive sheet.

It is furthermore an object of the invention to provide an improveddrying apparatus which can readily dry a copying paper withoutdestroying the image thereon.

With the above and other objects in view, the invention will becomeapparent from the following detailed description taken in connectionwith the accompanying drawing, in which:

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a diagrammatic cross sectionalview of a drier means according to the present invention;

FIG. 2 is a cross sectional view taken longitudinally through anelectrophotographic apparatus provided with the improvements of theinvention;

FIG. 3 is a rear view of the apparatus illustrated in FIG. 2; and

FIG. 4 is a partially diagrammatic view showing the passage of dried andheated air through the apparatus of the invention.

DETAILED DESCRIPTION A copying paper 2 which has been developed in adeveloper tank 1 is squeezed by a pair of squeegee rollers 3 and 4 whichare placed just after the developer tank 1.

The squeegee rollers consist of a metallic roller 3 and a rubber roller4. The metallic roller 3 is electrically grounded. This has the effectof preventing an edge effect in the solid image area as well as ofpreventing the so-called offset effect of transferring the toner of theimage on the copying paper to the squeegee rollers. Furthermore, themetallic roller 3 promotes the development of the coping paper with thedeveloper solution being squeezed out to the entrance of the copyingpaper to the squeegee rollers.

The copying paper 2 which has passed through the squeegee rollers isfurther transferred by a pair of drying rollers 5 and 6. Thephotosensitive surface of the copying paper 2 is difficult to dry,especially, when a metallic roller is used. A blotter roller istherefore provided on the side of the photosensitive surface. Thus theupper roller 5 of the drying rollers has a liquid-absorbing materialsuch as blotting paper, liquid-absorbing felt or the like on theperipheral surface 8 of a metallic cylinder 7. The lower roller 6 ispreferably a metallic or a rubber roller. After passing through thesqueegee rollers 3 and 4, any film of developer solution which stillremains on the photosensitive surface is substantially removed duringthe passage of the copying paper through the drying rollers by beingpressed against the liquid-absorbing peripheral surface of the rollers5. Thereafter, the copying paper 2 follows a path 9 and exits from themachine through a pair of exit rollers 10 and 11.

A flow of air is discharged through an opening 12 from a blower andpasses around the roller 5 in the direction shown by arrow 13, andtravels to the right along the path 9 as shown by arrow 14, and exitsfrom the machine. The air flow mentioned above, in flowing around theroller 5, dries the peripheral surface 8 of the liquid-absorbingmaterial which has been dampened by the wet copying paper so that theperipheral surface is always kept dry to dry the copying paper mosteffectively.

It is preferable that the air flow mentioned above be heated as this notonly promotes drying of the peripheral surface of the roller 5, but alsodries and finishes the copying paper which has passed through the dryingrollers 5 and 6. The heating of the air flow can be achieved by means ofan electric heater, and it is also possible to use the heat generated bya high-intensity lamp in the exposure station. The latter is quiteadvantageous in view of the available source of heat.

While the present invention has been particularly described in terms ofa specific embodiment thereof, it is to be understood that numerousvariations and modifications may be readily devised by those skilled inthe art without departing from the scope of the inventlon.

FIG. 2 illustrates an electrophotographic apparatus including theimprovements of the invention, said apparatus and improvements beingshown in greater detail than in FIG. 1.

The apparatus of FIG. 2 includes a casing having an upper station 22 atwhich photosensitive sheets may be placed for purposes of exposure, theexposure being effected through a mobile light source 24 details ofwhich are not essential to an understanding of the present inventionexcept for the fact that this system is a source of heat which isemployed for heating and drymg am When a copy sheet has been exposed atthe station 22 it is removed to section 26 whereat the sheet passesthrough rollers onto a perforated belt 28 having an internal chamber 30.The perforated belt is supported on rollers 32, 34, 36 and 38 by meansof which the belt 28 which is an endless belt is transported along anendless path.

As will be shown hereinafter air is evacuated from the internal chamber30 thereby sucking the paper against the belt whereby the paper iseffectively and positively transported towards and into a tank 40 whichis the developer tank and includes a liquid developer for developing theelectrostatic image which has been placed upon the copy sheet by aconventional technique which is well known in the art.

Supported downstream of the belt 28 and a guide 42 which serves todirect the copy paper in a curvilinear path are a pair of squeegeerollers 44 and 46, these squeegee rollers serve the purpose which hasbeen indicated hereinabove.

Downstream of the squeegee rollers is a pair of further or drier rollers48 and 50 whereof the roller 50 is the blotter roller and is providedwith a liquid-absorbing material such as blotter paper or the like- Thecopy paper moves through the developer tank 40 and through the squeegeerollers 44 and 46, passing thereafter through the drier rollers 48 and50 and than exiting from the machine through a pair of rollers 52 and54, the latter being supported on a spring 56 for the firm and effectiveguiding of the copy paper from the machine.

In FIG. 3 appears a blower 58 the purpose of which is to transport theheated and dried air as referred to generally hereinabove. Alsoappearing in FIG. 3 is an air manifold 60 the function of which willbecome apparent hereinafter. Other parts of the apparatus illustrated inFIG. 3 such as for example the control circuitry 62 while beingessential to the operation of the equipment of purposes of reproductionare not essential to an understanding of the present invention andconsequently will not be explained in detail in this text.

Referring next to FIG. 4 it is seen that the blower 58 has a suctionside connected through a hood 64 and an opening 66 to the internalchamber 30 of the perforated belt 28 at a consequence whereof air issucked from the chamber 30 and is caused to flow through the blower 58and an opening 68 into the channel 70 which passes by at least one andpreferably a series of lamps 72 which are a part of the mobile system 24referred to hereinabove with respect to FIG. 2. By coming into contactand flowing past such lamps the air evacuated from internal chamber 30is heated and dried and is as a consequence available for the drying ofthe blotter material referred to hereinabove and for drying the copypaper itself.

Air from the channel 70 passes into an opening 74 and into manifold 60and out through opening 76 to flow across the blotter material of theroller 50 and thence along the path indicated by arrow 78 to come in tocontact with and engage the copy paper directly for a drying of thesame.

Stated otherwise the air from the internal chamber of the perforatedbelt is discharged into a channel in which is located the mobile opticalsystem, the movement of the air being effected by a blower. The heatedand dried air is discharged as copy sheet drying air while this air alsohas the effect of cooling the lamps in the mobile optical system. Thisair dries the blotter roller since the material of the blotter roller isespecially susceptible of being dried by the mobile heated air being forexample of a material such as ordinary blotting paper.

In general the system of the invention is characterized by the fact thatthe air evacuated from the internal chamber of the perforated belt isemployed as cooling air for the exposure lamps whereafter the thuslyheated and dried air is employed to dry the blotter roller andthereafter employed for drying the surfaces of the copy sheetsthemselves.

In the aforesaid apparatus the driving of the squeegee and blotterrollers is performed through a common gear train, these rollers thusbeing characterized by the same peripheral speed.

From the above it will be seen that there is provided a copy paper dryerfor a liquid developing type electrophotographic reproduction apparatuswhich comprises a light source for the exposure of a photosensitivesheet, a developer tank containing a liquid developer and means feedingthe exposed photosensitive sheet into and through the liquid developerin the tank, said means including a perforated endless belt defining aninternal chamber and adapted to engage the aforesaid sheet. Furthermore,there is provided a pair of squeegee rollers at the exit of the tank toreceive the sheet therefrom and a pair of drier rollers positionedadjacent and downstream of the squeegee rollers for receiving the sheettherefrom. One of the drier rollers includes an outer coating of aliquid-absorbing material, the other of the drier rollers beingconstituted of a hard material and pressing the photosensitive sheetinto pressure contact with the first said roller. Furthermore, there isprovided means to evacuate air from the internal chamber of theaforesaid perforated belt and move the same past the light source toheat and dry the air and to discharge the thusly heated and dried air,first against the liquid-absorbing material of the blotter roller andthen into contact with the photosensitive sheet.

There will now be obvious to those skilled in the art many modificationsand variations of the structure set forth hereinabove. Thesemodifications and variations will not depart from the scope of theinvention if defined by the following claims.

What is claimed is:

l. A copy paper drier for a liquid development type electrophotographicreproduction apparatus which comprises a light source for the exposureof a photosensitive sheet, a developer tank containing a liquiddeveloper, means for feeding the exposed photosensitive sheet into andthrough the liquid and downstream of the squeegee rollers for receivingthe sheet therefrom, one of said drier rollers including an outercoating of a liquid-absorbing material, the other of the drier rollersbeing constituted of a hard material and pressing the photosensitivesheet into pressure contact with said one drier roller, and means toevacuate air from the internal chamber of said belt and move the samepast said light source to heat and dry the air and to discharge thethusly heated and dried air first against said liquid-absorbing materialof said roller and then into contact with said photosensitive sheet.

2. Adrier as claimed in claim 1 wherein said evacuating means includesan air duct and said one drier roller has an upper portion whichprojects into said duct, said sheet passing from said drier rollers intosaid duct.

3. A drier as claimed in claim 2 wherein said liquidtqk iifi i a c ai rngifiii i: 31 2 comprising exit rollers in said duct for engaging saidsheet to pass the sheet from said duct, the air passing through saidduct with said sheet towards said exit rollers.

5. A drier as claimed in claim 2 wherein said evacuating means includesa blower having a suction side coupled to the internal chamber of saidbelt.

6. A drier as claimed in claim 2 wherein said light source is a highintensity lamp.

7. A drier as claimed in claim 1 wherein one of said squeegee rollers ismetallic and the other of said squeegee rollers is rubber.

8. A drier as claimed in claim 7 comprising means grounding the metallicsqueegee roller.

9. A drier as claimed in claim 8 wherein said one drier roller includesan inner annular metallic portion covered by said liquid-absorbingmaterial.

1. A copy paper drier for a liquid development type electrophotographicreproduction apparatus which comprises a light source for the exposureof a photosensitive sheet, a developer tank containing a liquiddeveloper, means for feeding the exposed photosensitive sheet into andthrough the liquid developer in the developer tank, said means includinga perforated endless belt defining an internal chamber and adapted toengage said sheet, a pair of squeegee rollers at the exit of the tank toreceive said sheet therefrom, a pair of drier rollers positionedadjacent and downstream of The squeegee rollers for receiving the sheettherefrom, one of said drier rollers including an outer coating of aliquid-absorbing material, the other of the drier rollers beingconstituted of a hard material and pressing the photosensitive sheetinto pressure contact with said one drier roller, and means to evacuateair from the internal chamber of said belt and move the same past saidlight source to heat and dry the air and to discharge the thusly heatedand dried air first against said liquid-absorbing material of saidroller and then into contact with said photosensitive sheet.
 2. A drieras claimed in claim 1 wherein said evacuating means includes an air ductand said one drier roller has an upper portion which projects into saidduct, said sheet passing from said drier rollers into said duct.
 3. Adrier as claimed in claim 2 wherein said liquid-absorbing material isblotter paper.
 4. A drier as claimed in claim 2 comprising exit rollersin said duct for engaging said sheet to pass the sheet from said duct,the air passing through said duct with said sheet towards said exitrollers.
 5. A drier as claimed in claim 2 wherein said evacuating meansincludes a blower having a suction side coupled to the internal chamberof said belt.
 6. A drier as claimed in claim 2 wherein said light sourceis a high intensity lamp.
 7. A drier as claimed in claim 1 wherein oneof said squeegee rollers is metallic and the other of said squeegeerollers is rubber.
 8. A drier as claimed in claim 7 comprising meansgrounding the metallic squeegee roller.
 9. A drier as claimed in claim 8wherein said one drier roller includes an inner annular metallic portioncovered by said liquid-absorbing material.